USB-C CC Pull-Down Circuit Using ESD Protection for Fast Role Swap
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Solution Overview
Problem
Existing USB technologies require multiple resistors with large resistance values in parallel for electrostatic discharge protection, which increases circuit board design area and complexity when generating a pull-down signal for fast role swap (FRS) functions.
Innovation Solution
An electronic device with a USB power delivery function that uses an ESD protection circuit to generate a pull-down voltage through a pull-down path, eliminating the need for multiple resistors in parallel, and incorporating a control circuit to manage power reception and electrostatic protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple resistors with large resistance values are connected in parallel for electrostatic discharge protection, then the electrostatic protection function is improved, but the circuit board design area increases
Solution Approach 1:
The patent combines the electrostatic discharge protection function with the pull-down signal generation function into a single integrated circuit. The ESD protection circuit includes a pull-down path that can serve dual purposes: protecting against electrostatic discharge and generating the pull-down signal for fast role swap operations. This merging eliminates the need for separate resistor components, thereby reducing circuit board design area while maintaining both functions.
Solution Approach 2:
The pull-down path within the ESD protection circuit is designed to perform multiple functions. It can operate as an electrostatic discharge path during ESD events and as a pull-down signal generation path during normal FRS operations. This multi-functionality allows a single circuit element to replace what would traditionally require separate components, reducing overall circuit board area.
2Ease of operation
If multiple resistors with large resistance values are connected in parallel for pull-down signal generation, then the pull-down signal generation function is improved, but the device complexity increases
Solution Approach 1:
The patent merges the pull-down signal generation function into the ESD protection circuit structure. The control circuit activates the pull-down path of the ESD protection circuit to generate the pull-down signal, eliminating the need for separate resistor networks. This integration reduces device complexity by consolidating multiple functions into a single circuit block.
Solution Approach 2:
The ESD protection circuit is designed to provide its own pull-down signal generation capability through its existing pull-down path. When the control circuit activates it, the same circuit structure that protects against electrostatic discharge also generates the necessary pull-down signal for role swapping. This self-service approach eliminates the need for additional dedicated pull-down signal generation circuitry.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces circuit board design area and complexity while enabling efficient power management and electrostatic protection during FRS operations, allowing the device to switch between power supply and reception roles without additional circuitry.
Implementation Method 1
a CC is generally coupled to (for example, electrically connected in parallel to) an electrostatic discharge (ESD) protection circuit
Data Source
AI summary
An electronic device having a universal serial bus (USB) power delivery function includes a connector, an electrostatic discharge (ESD) protection circuit, a power reception notification circuit, and a control circuit. The connector is coupled to a USB host. The connector includes a configuration channel (CC) pin. The power reception notification circuit is configured to turn on, in response to an enable signal, a pull-down path of a pull-down circuit of the ESD protection circuit. The configuration channel pin generates a pull-down voltage through the pull-down path of the pull-down circuit when the pull-down path is turned on. The control circuit is configured to send the enable signal to the power reception notification circuit when a trigger signal that meets a power reception condition is detected. The control circuit controls the connector to draw power from the USB host when the pull-down voltage of the connector is greater than a pull-down threshold.